The present invention relates to a spring rod for a strap such as a watch strap.
A conventional spring rod for a watch strap has a structure as shown in FIG. 1. A cylinder 1 is tapered at its two ends 1a and 1b, and houses sliders 2a and 2b therein. Projections 3a and 3b each having two annular ribs formed thereon are formed on the distal ends of the sliders 2a and 2b, respectively. A spring 4 serves to constantly urge the sliders 2a and 2b outward.
In order to mount a spring rod of the structure as described above, the projection 3a is inserted in a hole 6a of a mounting arm 5a of the watch. Then, by pushing the portion of the projection 3b between the annular ribs toward the cylinder using a small member such as a branch member or needle, so that the projection 3b is inserted into the cylinder 1, the spring rod can be fitted between mounting arms 5a and 5b. When the projection 3b opposes a hole 6b of the mounting arm 5b, the small member is released from the projection 3b. Then, the projection 3b is inserted into the hole 6b by the biasing force of the spring 4.
However, in a spring rod of this structure, engagement between the small member and the projection is difficult to attain. Therefore, mounting of such a spring rod between mounting arms is difficult.